Silicon rubber keypads are used in a variety of electronic products ranging from telephones to calculators. Manufacturers of these products typically want to extend the life of these products for as long as possible. This is particularly desirable for widely known manufacturers having a reputation for providing highly reliable products.
Unfortunately, the use of silicon rubber keypads in electronic products can result in the premature failure of the electronic products. For example, a cellular telephone is typically constructed with a printed circuit board and a mating silicon rubber keypad. The printed circuit board will typically have a plurality of electrically conductive contacts formed on its mating surface, and the silicon rubber keypad will typically have a corresponding plurality of electrically conductive contacts associated with its mating surface. In operation, a user of the cellular telephone will use his/her fingers to apply pressure to the silicon rubber keypad so as to cause electrical connections to be made between corresponding electrically conductive contacts.
Over time, the silicon rubber keypad usually comes into contact with contaminants such as creams, lotions, and oils. These contaminants may come directly from the fingers of the user or from some other source. Regardless of where they originate, these contaminants may permeate through the silicon rubber keypad and cause corrosion and connection problems with the electrically conductive contacts. This permeation is usually aided by the application of pressure to the silicon rubber keypad.
In view of the foregoing, it would obviously be beneficial to provide a means for preventing contaminants from permeating through the silicon rubber keypad or for preventing contaminants, which may permeate through the silicon rubber keypad, from permeating beyond the silicon rubber keypad so as to prevent corrosion and connection problems with the electrically conductive contacts. In broader terms, it would be beneficial to provide a means for preventing contaminants from permeating through or beyond any type of substrate material which would otherwise allow such contaminant permeation to occur.